Tablets are a great way for getting a medicine from outside your body > into your body! They work like a little delivery van to carry a drug into your body, in fact sometimes we do call them ‘vehicles’!
They are often made from compacted powder and the more compacted they are the harder they are to dissolve in the stomach, meaning that this can delay how quickly the drug dose takes to come out. Other chemicals can speed/slow this process too.
If you want to treat a headache you want the tablet to dissolve quickly so the pain goes away! If you want to treat a persistent problem (like a stomach ulcer) you want this to be sloooooooow release so it can work for hours!